1. Field of the Invention
The invention relates to an optical distribution frame, more particularly intended for allowing interconnections which are made selectively between optical fiber links in a telecommunication installation comprising a large number of these fiber links.
It also relates to a method intended for making jumper connections between fibers by means of which these interconnections are made, in an optical distribution frame having a high density of interconnection points, as envisioned above.
2. Description of the Prior Art
U.S. Pat. No. 5,497,444 describes one example of an optical distribution frame for use in telecommunication installations. It is shown in FIG. 1 and has a rectangular framework 1 which carries a series of horizontal supports 2 on which are placed modules 3 which are arranged on the supports so that they constitute two parallel vertical subassemblies. Each module is designed to accommodate a plurality of connectors, each connector being adapted to interconnect two fibers, one of which is used as a jumper. This kind of interconnection of two fibers is effected by means of two connection members each of which is fitted to the end of a fiber and which are placed opposite each other at a connector. The fiber connection members serving as jumpers are placed in front of the connectors in the distribution frame and the connection members of the other fibers that they interconnect are placed behind them. Support and guide members are provided for organizing the passage of the jumpers between the connectors, allowing for future reorganization requirements, and in FIG. 1 are represented by split rings 4 and troughs 5.
For reasons of orderliness and safety, the jumpers generally either run horizontally in horizontal troughs, and in particular in troughs associated with the horizontal supports of the modules, or vertically, to be more specific in split rings defining a vertical guide at each widthwise end of the distribution frame. For reasons of standardization, the optical jumpers, which are usually manufactured in a factory, are generally of a particular length sufficient to connect the farthest apart connection members of the distribution frame, and the jumpers connecting connection members that are less far apart must be coiled up in order to accommodate their excess length within the distribution frame. They are accommodated inside or in the vicinity of the vertical guides, for example, and specific provision must therefore be made for this.
This kind of solution was initially developed for jumpers consisting of electrical wires, and is not satisfactory if the distribution frame to be produced is a high-density distribution frame with a very high capacity, involving the fitting of a very large number of optical jumpers, for example ten thousand or more, which may be fragile and which must therefore be protected from damage, in particular during reorganization.
It therefore becomes preferable to provide an automated means of fitting the jumpers, as envisaged in French patent 2648300 when the number of jumpers to be fitted is of the order of that given as the example above and when, in consequence, the management of the excess lengths and the manual interventions to be made in a high-density environment of connection members become predominant aspects.
U.S. Pat. No. 6,157,766 discloses a high-density optical distribution frame for selectively interconnecting optical fiber links by means of jumpers which also consist of optical fibers within the context of a telecommunication installation.
This distribution frame comprises two vertical racks, the connection areas of which are lateral, facing one another, and which are separated from one another by an area for housing jumpers, these jumpers connecting the connection areas of each rack. The connection areas can pivot about a lower lateral horizontal shaft.
Such a distribution frame poses the following essential technical problem: it is very bulky.
This is because firstly the jumpers are precut to a fixed length and must be stored in a magazine (not shown in that document). Such a magazine may have a volume equivalent to that of the distribution frame.
Next, given the length and the admissible curvature of the jumpers, the area receiving them must be relatively wide, thereby further increasing the overall size of such a type of distribution frame.
Another technical problem relates to the fact that the connection areas can move and consequently the optical fibers are displaced during connections. This may cause interference in the telecommunications.